Add configured service port defaults

serve.go

@@ -142,6 +142,13 @@ func (service *Service) Serve(bind string, port int) (*DNSServer, error) {
 //	defer func() { _ = runtime.Close() }()
 //	fmt.Println("dns:", runtime.DNSAddress(), "health:", runtime.HTTPAddress())
 func (service *Service) ServeAll(bind string, dnsPort int, httpPort int) (*ServiceRuntime, error) {
+	if dnsPort == 0 {
+		dnsPort = service.dnsPort
+	}
+	if httpPort == 0 {
+		httpPort = service.httpPort
+	}
+
 	dnsServer, err := service.Serve(bind, dnsPort)
 	if err != nil {
 		return nil, err
@@ -159,6 +166,17 @@ func (service *Service) ServeAll(bind string, dnsPort int, httpPort int) (*Servi
 	}, nil
 }
 
+// ServeConfigured starts DNS and health using the ports stored on the service.
+//
+//	service := dns.NewService(dns.ServiceOptions{
+//		DNSPort:  1053,
+//		HTTPPort: 5554,
+//	})
+//	runtime, err := service.ServeConfigured("127.0.0.1")
+func (service *Service) ServeConfigured(bind string) (*ServiceRuntime, error) {
+	return service.ServeAll(bind, service.dnsPort, service.httpPort)
+}
+
 type dnsRequestHandler struct {
 	service *Service
 }

service.go

@@ -69,6 +69,8 @@ type Service struct {
 	reverseIndex                 *cache.Cache
 	treeRoot                     string
 	zoneApex                     string
+	dnsPort                      int
+	httpPort                     int
 	lastAliasFingerprint         string
 	hsdClient                    *HSDClient
 	mainchainAliasClient         *MainchainAliasClient
@@ -96,6 +98,8 @@ type ServiceOptions struct {
 	Records                      map[string]NameRecords
 	RecordDiscoverer             func() (map[string]NameRecords, error)
 	FallbackRecordDiscoverer     func() (map[string]NameRecords, error)
+	DNSPort                      int
+	HTTPPort                     int
 	HSDURL                       string
 	HSDUsername                  string
 	HSDPassword                  string
@@ -162,6 +166,8 @@ func NewService(options ServiceOptions) *Service {
 		reverseIndex:                 buildReverseIndexCache(cached),
 		treeRoot:                     treeRoot,
 		zoneApex:                     computeZoneApex(cached),
+		dnsPort:                      options.DNSPort,
+		httpPort:                     options.HTTPPort,
 		hsdClient:                    hsdClient,
 		mainchainAliasClient:         mainchainClient,
 		chainAliasActionCaller:       options.ChainAliasActionCaller,

service_test.go

@@ -5,8 +5,10 @@ import (
 	"encoding/json"
 	"errors"
 	"io"
+	"net"
 	"net/http"
 	"net/http/httptest"
+	"strconv"
 	"strings"
 	"sync/atomic"
 	"testing"
@@ -33,6 +35,23 @@ func exchangeWithRetry(t *testing.T, client dnsprotocol.Client, request *dnsprot
 	return nil
 }
 
+func pickFreeTCPPort(t *testing.T) int {
+	t.Helper()
+
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("expected free TCP port: %v", err)
+	}
+	defer func() { _ = listener.Close() }()
+
+	tcpAddress, ok := listener.Addr().(*net.TCPAddr)
+	if !ok {
+		t.Fatalf("expected TCP listener address, got %T", listener.Addr())
+	}
+
+	return tcpAddress.Port
+}
+
 func TestServiceResolveUsesExactNameBeforeWildcard(t *testing.T) {
 	service := NewService(ServiceOptions{
 		Records: map[string]NameRecords{
@@ -441,6 +460,45 @@ func TestServiceServeAllStartsDNSAndHTTPTogether(t *testing.T) {
 	}
 }
 
+func TestServiceServeConfiguredUsesPortsFromServiceOptions(t *testing.T) {
+	dnsPort := pickFreeTCPPort(t)
+	httpPort := pickFreeTCPPort(t)
+
+	service := NewService(ServiceOptions{
+		DNSPort:  dnsPort,
+		HTTPPort: httpPort,
+		Records: map[string]NameRecords{
+			"gateway.charon.lthn": {
+				A: []string{"10.10.10.10"},
+			},
+		},
+	})
+
+	runtime, err := service.ServeConfigured("127.0.0.1")
+	if err != nil {
+		t.Fatalf("expected configured runtime to start: %v", err)
+	}
+	defer func() {
+		_ = runtime.Close()
+	}()
+
+	_, dnsActualPort, err := net.SplitHostPort(runtime.DNSAddress())
+	if err != nil {
+		t.Fatalf("expected DNS address to parse: %v", err)
+	}
+	if dnsActualPort != strconv.Itoa(dnsPort) {
+		t.Fatalf("expected configured DNS port %d, got %s", dnsPort, dnsActualPort)
+	}
+
+	_, httpActualPort, err := net.SplitHostPort(runtime.HTTPAddress())
+	if err != nil {
+		t.Fatalf("expected HTTP address to parse: %v", err)
+	}
+	if httpActualPort != strconv.Itoa(httpPort) {
+		t.Fatalf("expected configured HTTP port %d, got %s", httpPort, httpActualPort)
+	}
+}
+
 func TestServiceDiscoverReplacesRecordsFromDiscoverer(t *testing.T) {
 	records := []map[string]NameRecords{
 		{